The present invention relates to the field of instrumented antifriction bearings equipped with an assembly for detecting rotation parameters such as the angular rotation, the direction of rotation, the speed and/or the acceleration.
In a way which is known, for example, from document EPA-0 327 434, an instrumented antifriction bearing generally comprises a detection assembly consisting of a sensor secured to the non-rotating ring of the bearing and of an encoder secured to the rotating ring of the bearing. The encoder rotates past the sensor in such a way that the sensor generates a signal that represents the rotation parameters of the encoder, for example a sinusoidal or squarewave electrical signal, the frequency of which is proportional to the rotational speed of the encoder. The encoder may be of multi-pole magnetic or of optical type and operates in collaboration with a sensor of corresponding type, that is to say a magneto-sensitive sensor in the case of a magnetic encoder and an optical sensor in the case of an optical encoder. The sensor and the encoder are arranged on one side of the bearing, each being fixed to the corresponding ring by means of a support. Each of the supports is fixed by push-fitting onto a cylindrical bearing surface of the corresponding ring, which is machined for that purpose.
To prevent the ingress of external contaminants likely to degrade the operation of the detection assembly and the operation of the bearing, seals are provided on each side of said bearing. On the opposite side to the detection assembly, a seal formed of a metal end plate over which a supple portion is overmolded is fixed into an annular groove in the outer ring. A lip originating from the supple portion rubs against a rubbing surface of the inner ring. On the same side as the detection assembly, a seal also made up of a metal end plate and of a supple portion is fixed to a bore of the sensor support. A lip originating from the supple portion rubs against a rubbing surface of the support of the encoder means.
The special-purpose machining operations required for fixing the encoder and the sensor which are mounted on their supports are expensive and relatively bulky.
Furthermore, in the case of a detection assembly of optical type it is necessary to avoid the ingress of bearing lubricant between the encoder and the sensor.
It is an object of the present invention to overcome the disadvantages of the devices of the prior art.
It is an object of the present invention to propose an instrumented antifriction bearing in which the rings are of standard type designed to be used both with or without detection assembly, and comprising a seal between the rolling elements and the gap between the sensor and the encoder.
The instrumented antifriction bearing device according to the invention is of the type provided with a non-rotating part comprising a non-rotating ring and a sensor means, with a rotating part comprising a rotating ring and an encoder means, and with at least one row of rolling elements arranged between two raceways of the non-rotating and rotating rings, the sensor means being fixed in a groove of the non-rotating ring arranged near a radial lateral face of said non-rotating ring. The non-rotating part further comprises a sealing means arranged axially between the sensor means and the rolling elements substantially at the groove, the sealing means being distinct from the sensor means.
A seal is thus provided between the sensor means and the rolling elements. The sensor means may be fixed in a standard groove able, in other uses, to accommodate a seal. The encoder means may be fixed to a standard bearing surface of the rotating ring able to collaborate, in other uses, with a seal. It is thus possible to use inexpensive standard rings manufactured and used in great numbers for sealed antifriction bearings of the xe2x80x9cISOxe2x80x9d series, which have no means of measuring rotation parameters. The gap between the encoder and the sensor is effectively isolated from the lubricant placed in the bearing.
An antifriction bearing with information sensor is thus obtained very economically from elements of a conventional basic antifriction bearing, which elements can be chosen from the xe2x80x9cISOxe2x80x9d range of the bearing manufacturers.
Advantageously, the non-rotating ring comprises two grooves arranged one on each side of the rolling elements. The profiles of the two grooves may be identical. The non-rotating ring may be symmetric with respect to a plane passing through the center of the rolling elements.
Advantageously, the sensor means comprises a support, a part of which is arranged in said groove with the non-rotating ring for the fixing of said sensor means to said non-rotating ring. The part arranged in said groove may be of a diameter larger than that of the remainder of the support. The sensor support here is mounted in the place of a conventional bearing seal.
In one embodiment of the invention, the sealing means is arranged radially between a support of the sensor means and the rotating ring.
Advantageously, the sealing means comprises a substantially radial portion of annular shape and an attachment portion in contact with the sensor means. The attachment portion may collaborate with the support of the sensor means. The attachment portion may be mounted with radial gripping on the sensor means.
In one embodiment of the invention, the attachment portion of the sealing means is also in contact with the non-rotating ring.
In one embodiment of the invention, the attachment portion of the sealing means comprises a bulge made of supple material. The bulge may project into said groove and be in contact both with the support of the sensor means and with the non-rotating ring. The bulge may contribute to holding the support of the sensor means in place.
In another embodiment of the invention, the attachment portion of the sealing means comprises an oblique rim originating from the substantially radial portion.
Advantageously, the sensor means comprises an opening for mounting the sealing means, which opening is situated opposite the rolling elements and allows said sealing means to be introduced into the sensor means toward the rolling elements.
Another subject of the present invention is a method of assembling an instrumented antifriction bearing device. The bearing is of the type provided with a non-rotating part comprising a non-rotating ring and a sensor means, with a rotating part comprising a rotating ring and an encoder means, and with at least one row of rolling elements arranged between two raceways of the non-rotating and rotating rings, in which a sealing means is placed axially between the sensor means and the rolling elements, the sealing means being distinct from the sensor means, the sensor means being fixed in a groove of the non-rotating ring arranged near a radial lateral face of said non-rotating ring, the sealing means being arranged substantially at the groove.
The sealing means may radially grip the sensor means. The sealing means may be mounted via an opening in the sensor means situated opposite the rolling elements.
It is possible to mount the support of the sensor means, then the sealing means, then the rest of the sensor means, said support leaving an opening for the passage of the sealing means. These steps of assembly employ simple movements which can be performed economically using a press.